The goal of many surgical procedures is to remove, and/or remove so as to shape, body tissue at the site at which the procedure is performed. Surgery on the nasal and sinus cavities and/or the throat frequently involves performing this type of selective removal of tissue. For example, sinus surgery often involves the removal of diseased membranes and/or bone partitions and/or malformed portions of sinus tissue, sometimes referred to as the sinus layer, and bony material entrained in this layer. Orthopedic surgery involves the shaping of bones and soft tissue that form the joints of the skeletal system.
A number of surgical instruments and tools have been developed to facilitate the performance of these surgical procedures. For example, the Applicant's Assignee manufactures a line of surgical tools under the trademark HUMMER that are especially designed to perform nasal, sinus and throat surgery. This line of tools includes a handpiece with an electrically driven motor. Different cutting accessories are designed to selectively be connected to the handpiece. Each cutting accessory typically has a hollow rotating or reciprocating shaft that is housed in a fixed, tube-like, housing. Irrigating solution is flowed to the distal end of the cutting accessory, the end applied to the surgical site, through an annular space between the moving shaft and the complementary housing. This fluid is then drawn away from the surgical site by a suction that is applied through the rotating or reciprocating shaft. This fluid serves as a transport media that flushes debris proximally, away from the patient.
While current surgical tools have proven useful, there are some limitations associated with their use. For example, many surgical handpieces and their complementary attachments are provided with conduits through which suction can be drawn from the complementary attached cutting accessory. Collectively, these handpieces and cutting accessories are constructed so that the coupling of the cutting accessory to the handpiece results in the establishment of a fluid communications path between the suction channel in the cutting accessory and the suction conduit in the handpiece.
However, to date, it has proven difficult to provide a surgical tool system that, upon attachment of the cutting accessory to the handpiece, establishes a fluid path through which irrigating solution is supplied to the cutting accessory. In many commercially available surgical tool systems, in order to establish this fluid path, medical personnel must manually connect a small flexible irrigation fluid supply line associated with the handpiece to an inlet fitting integral with the cutting accessory. Requiring medical personnel to perform this task, and disconnect the line when the accessory is removed from the handpiece, adds to the overall time it takes to remove, replace or change the accessory.
There have been some surgical tool systems proposed that include handpieces with complementary irrigation fluid outlet ports. These systems are designed so that the complementary cutting accessory must be precisely aligned with the handpiece in order to establish the desired fluid communications path. Thus, when a new accessory is fitted to one of these handpieces, care must be taken to properly align these two components. Again, requiring medical personnel to perform this step adds to the overall time it takes to fit the new accessory to the handpiece.
Moreover, in the known surgical tool systems, the need to precisely align the cutting accessory with the handpiece means that the cutting element integral with the cutting accessory must be placed in a select, fixed orientation relative to the handpiece. Thus, in these systems, the surgeon is not able to position the cutting accessory so that, relative to the handpiece, the cutting element is in an orientation that makes it more convenient, or even possible, for the surgeon to perform some surgical tasks.
Moreover, like any motor, the motors integral with handpieces of surgical tool systems only operate within a given operating range. The motors integral with some handpieces operate within a relatively limited rotational speed range. This is especially true for handpieces that include brushless, sensorless motors. These motors, owing to the fact that the back EMF signals they produce are employed to control their operation, have operational rotational speed ranges that are less than similar motors in which sensors are installed that provide an indication of rotor position.
The limited rotational speed range of some handpiece motors means that the accessories attached to these headpieces can only be driven through a relatively limited range of speeds. This means that sometimes a cutting accessory, such as a laryngeal cutter cannot be driven at a relatively low speed that might be useful. Similarly, another accessory, such as a bur cannot be driven at a relatively high speed that may be sometimes desired for its operation.
One solution to this problem is to provide the surgeon with two different handpieces; one with a relatively slow speed motor, the second with a relatively high speed motor. A second solution to this problem has been to provide intermediate attachments between the handpiece and the cutting accessory. Typically, this attachment is connected to a handpiece with a relatively high speed motor. Internal to the attachment is a gear assembly that reduces the output speed at which the associated accessory is driven. A disadvantage of both of these solutions is they require the introduction of an extra component, either the supplemental handpiece or the ancillary attachment to the operating room. Moreover, the medical personnel using the components of these systems must spend time ensuring that the cutting accessory is attached to the appropriate handpiece or intermediate attachment in order to operate the accessory at the desired speed. The time making sure this connection is established adds to the overall time it takes to make the cutting accessory available to perform the desired surgical procedure.